Heat pumps for landlords in Cardiff

Cardiff’s rental market and what it means for heating

Cardiff is a big private rented city: 24.3% of its 147,333 households, about 35,785 households, rent privately (Census 2021). That is a large pool of landlords weighing up the same question, and the housing mix shapes the answer. Terraced homes are 29.6% of households, semis 29.7%, detached 14.1% and flats 20.2%, with a further 5.0% in converted buildings.

Heating is mostly mains gas (78.4% of households), so a heat pump usually means replacing a working gas boiler. Another 10.4% rely on electric heating alone. Oil is 0.1%, which means the higher oil and LPG grant is rarely relevant in Cardiff.

Which rules apply in Wales and which do not

Two England only measures do not reach Cardiff: the Renters’ Rights Act changes and Warm Homes: Local Grant. Do not rely on guidance that says “landlords” without naming the country.

What does apply:

• Boiler Upgrade Scheme (England and Wales): £7,500 for an air to water or ground source heat pump, £2,500 for air to air, one grant per property, installed by an MCS installer who applies for you.
• Planned EPC C minimum standard (England and Wales): government has said EPC C by 1 October 2030 with a £10,000 cost cap. The regulations are expected in 2027 and have not been laid, so treat it as planned, not law. Today’s rule is minimum EPC E.
• Renting Homes (Wales) Act 2016: the Welsh Government guidance says a landlord must keep the home fit for human habitation when the contract-holder moves in and throughout the contract. Its list of matters includes damp and mould, cold and heat. A cold, damp rental is a legal problem in Wales, not only a comfort one.

Planning rules for a heat pump in Cardiff

Wales has its own permitted development rules, so England’s Class G does not apply. According to the Welsh Government planning page, effective 1 June 2026:

• up to two air source heat pumps on a detached house, one on any other home;
• the outdoor unit, including any housing, must not exceed 1.5 cubic metres;
• the installation must meet the MCS 020(a) noise assessment;
• no unit on a pitched roof, and flat roof units must sit at least one metre from the roof edge;
• the right does not cover listed buildings;
• in a conservation area, no unit on a wall or roof facing a highway, and none closer to the highway than the house;
• outside conservation areas, no unit on a wall facing a highway.

The page is written for dwellinghouses. For a flat, a listed building or a house in a conservation area, ask Cardiff Council before you commit. Cardiff Council is the local planning authority for the city.

What the running costs look like

The Ofgem cap for 1 October to 31 December 2026 is 26.32p a kWh for electricity and 7.97p for gas. Electricity carries no VAT until 31 March 2027. A gas boiler at 90% efficiency costs about 8.86p per kWh of heat. A heat pump at a seasonal efficiency (SCOP) of 3.0 costs about 8.77p, and at 3.5 about 7.52p.

Heating	Cost per kWh of heat	Annual cost, 12,000 kWh of heat
Gas boiler, 90% efficient	8.86p	£1,063
Heat pump, SCOP 3.0	8.77p	£1,053
Heat pump, SCOP 3.5	7.52p	£902

Worked example (modelled, not a real project)

Inputs from this site’s model: a three bedroom semi needing 12,000 kWh of heat a year, the unit rates above, standing charges excluded. A heat pump saves about £10 a year at SCOP 3.0 and about £160 at SCOP 3.5. Small flats and terraces use less heat, so the saving is smaller. Many Cardiff rentals will not save much on bills, which matters if your tenant pays them.

Cost and funding for a Cardiff landlord

The Energy Saving Trust gives around £12,000 for a typical air source heat pump before grant. After the £7,500 Boiler Upgrade Scheme grant that leaves around £4,500, before any radiator, cylinder or electrical work. Installing a heat pump is 0% VAT until 31 March 2027 and 5% from 1 April 2027.

Nest is the Welsh Government’s home energy scheme. Its page says eligible households can get heat pumps, insulation and solar. That page does not set out private tenant or landlord conditions, so contact Nest before assuming a tenant qualifies. ECO4 closes on 31 December 2026.

When a heat pump is the wrong answer

Insulation and draught proofing come first in many Cardiff terraces, especially solid wall Victorian and Edwardian stock. A heat pump in a leaky house needs larger radiators and runs at poor efficiency. If the property is a small flat with no outdoor space, or you plan to sell soon, a better boiler and fabric work may serve you better. Hybrids are not grant funded. The hybrid guide covers when one still makes sense.

Next steps for a Cardiff rental

1. Look up the property’s EPC on the GOV.UK register and read its recommendations.
2. Check whether the home is a house, a flat or in a conservation area.
3. Use the EPC C deadline checker to see where the property stands against 2030.
4. Read the cost page and the Boiler Upgrade Scheme guide for landlords.
5. Use the landlord calculator or send an enquiry on the quote page. Relevant independent firms contact you; no charge to you, no obligation.